Nicky Morgan, the new women's minister, has indicated that the Conservatives are prepared to consider all-women shortlists if no progress is made on improving the party's proportion of female MPs at the election next year.

In comments to Mumsnet, the parenting website, Morgan said the party was taking the issue of women's representation very seriously, but not enough female candidates were coming forward.

In answer to a question about her views on all-women shortlists, she said: "I think we need to see where we end up in 2015 and if we are still struggling to get more women MPs then no option is off the table."

Morgan's comments are her first setting out her position on the issue since she became women's minister in April, replacing Maria Miller, who stood down over a scandal about her mortgage expenses.

Only 16% of Conservative MPs are women, compared to 33% of Labour MPs, while the Liberal Democrats have the worst ratio on 13%. Only three out of 27 members of David Cameron's cabinet are women.

While Labour pioneered the use of all-women shortlists, the Conservative and Liberal Democrat grassroots have strongly resisted the idea amid claims that local associations should be allowed to choose freely whom they want to represent them.

At the 2010 election, Cameron introduced an "A-list" of priority candidates for the most winnable seats that was roughly equally split between men and women, helping the party's number of female MPs to rise from 17 to 48.

However, that system was dropped after the election, and fewer than three in 10 candidates selected to stand in 2015 are women.

Cameron has been taunted frequently by Labour for having a "women problem", most recently when he turned up to a prime minister's questions with an entirely male frontbench.

He indicated in opposition that he could support all-women shortlists in some areas but he has not commented on the issue for some years and there were no mandated all-female shortlists at the 2010 election.

However, pressure on the prime minister to address the under-representation of women in his party is increasing, after Nick Clegg conceded that the Liberal Democrats may look at the idea and a number of prominent Conservative women called on Cameron to do more to increase female representation.

The Conservative former cabinet minister Caroline Spelman said this year that "nobody could argue with a 50:50 shortlist". The Tory peer Lady Jenkin said the party should consider all-female shortlists as it should not be seen as ignoring "50% of the talent".

"If the number of women MPs ends up retreating at the next election … we need to be considering all the options," Jenkin wrote in the Evening Standard. "That includes all-women shortlists, but also other things like postal ballots and primaries."